CD8A and diabetes mellitus: Similarly, TGF-β inhibits proliferation of naïve T cells but not antigen experienced cells in diabetes.27 However, a contrary report showed TGF-β1 attenuated effector function of tumor antigen-specific human memory CD8+T cells.28 The effects of TGF-β on naïve and preactivated T cells could be different due to downregulation of TGF-βRII expression on activated T cells.29 Thus, the timing of TGF-β inhibition and the mode of T cell stimulation play critical roles in determining its pleiotropic effects.